Metallic piston-packing.



H. W. RANSDALL. METALLIC EIS TON PACKING. APPLICATION FILED DEC- 31, I914v Patented Apr. 4, 1916.

Fig. 2.

'with a circumferential groove 3.

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HARRY W; RANSDALL, 0F INDIANAPOLIS, INDIANA, ASSIGNOIR, BY DIRECT AND MESNE ASSIGNMENTS, 0F ONE-THIRD TO THEODORE A. MEYER AND ONE-THIRD TO LAURENCE J. EBY, BOTH OF INDIANAPOLIS, INDIANA.

METALLIC PISTON-PACKING.

Specification of Letters Patent.

Application filed December 31. 1914. Serial No. 879,831.

To all whom it may concern Be it known that I, l'lARRY RAXSDALL, a citizen of the United States, residing at Indianapolis. Marion county, and State of Indiana, have invented and discovered certain new and useful Improvements in Metallie- Piston-Pacliings, of which the following is a specification.

My invention relates to pistons and its object is to provide packing rings of an effective character conforming to a cylinder of worn or irregular surface. thus tightly closing the cylinder against leakage of gas past the piston.

lVith this end in view my invention is embodied in preferable form in the device hereinafter described and illustrated in the accompanying drawings.

In these drawings, Figure lis a central cross sectirn' of the piston on line 1-1 of Fig. 2: Fig. 2 a section on line of Fig. 1: Fig. 3. a detailed enlarged sectional plan of expander ring oh'line 23 3 of Fig. 2; Fig. 4, a detail sectional plan of packing rings on line-l-l of Fig. 2; 7 detail enlarged sectional plan on line 55 of I am aware that it has heretofore been proposed to use metallic packing rings on a piston arranged with two outer rings adapted to bear against the cylinder wall and an inner so-called spreader ring, but in these constructions the outer and inner rings have been of the same thickness and same resiliency. With such an arrangement, if the spreader ring isstiff enough to provide an effective expansive action and the outer rings of the same strength. such outerrings will he too stiff to be conformed to an irregular cvlinder at all points, while if both sets of rings are made so light as to obtain the capacity for conforming to the cylinder, the inner ring Wlll not. possess sufficient expan sive orce. These objections are sought to be overcome by mv invention.

Referring to the drawings, 1 designates the wall of a cylinder in which the piston 2 is adapted to move. This piston is provided groove is seated a split spring ring 4 preferably of semi steel adapted to constitute thesole expanding means for the packing members. This ring is made thickest at. a point diametrically opposite the split, and tapers and Fig. 5 a- In this therefrom to the free ends, in order that the ring shall be of uniform resilience and that it shall be sufficiently yielding at the end portions. This ring when closed at its ends by insertion of the piston within the cylinder is of slightly greater interior diameter than that of the circumferential wall of the groove, whereby the ring is held slightly spaced from said wall under all conditions. The outer face ofthe ring hasinclined faces 5, meeting at the center and providing a wedge shaped peripheral surface.

Mounted within the groove and having in terior hearing against the expander ring and exterior hearing against the wall of the cylinder are metallic packing'rings 6, These rings are thin flexible strips of metal cut from an iron casting in circular form, and split. They possess no spring action apart from that due to the natural tendency of the cast. split, metal strip to yield and expand circularly. They are of uniform thick- Each ring has a radial sidewall 7 which bears against the adjacent side wall of the groove in the plston, and winch walls at all times serve to close the groove against the entrance of gas, but are no longer than necessary to merely perform this function. The outer edge of each such side wall of the ring joins a flat peripheral base wall 8, which bears against the surface of the cylinder. The inner edges of the peripheral faces of the two packing rings meet at the center line. The size and tension of the expander ring at, and the length of the side walls 7 are such that the outer edge of the expander ring at no time projects against the wall .of the cylinder.

The side and'peripheral walls of each packing ring are joined by a continuous inclined wallt), which meets the side and face walls at sharp acute angles.

The operation of the piston is as follows: To assemble the parts, the expander -ring and the packing rings are sprung into ed to force the packing said groove and of ments of their circumferences, and an inner I serving to force the the groove in the piston and the piston in serted in the cylinder. The pressure of the wall against the packing rings will contract them so that their ends almost touch and this pressure will be communicated to the spring expander forcing its ends together and imposing a tension on said expander. The expander when in contracted position being separated slightly from the inner Wall of the groove, has a contracting and expanding play within the groove which will serve to press the packing rings closely against the wall of the cylinder at all points thereof Whether the surface be regular or irregular. Owing to the thin orbss section of the pack ing rings, they are yield'able at localized portions of their circumference on arcs of short radii and hence will be forced to conform to the wall of the cylinder throughout the entire area thereof, the expander ring 4 packing rings outwardly by its spring action into any eccentric outward extension of the cylinder wall and to move toward the center of the piston to yield to any inward projection from the true circle of the cylinder.

The packing rings are of low cost, easily applied and may be readily replaced when they become worn.

Having thus described my said invention, what I claim is:

1. In combination with a piston, thin metallic circular packing rings of uniform thickness throughout yieldable'on short segeccentrically tapered expanderring adaptrings outwardly.

' 2. ln combination with apiston having a groove, continuous spring expander ring of comparatively stiff metal mounted in a width to fill the opening of the groove, said ring having outer inclined faces, outer triangular metallic packing rings each having an inclined face fitting a face of the expander ring, each of said outer rings being of thin cross section and less in thickness than the expander ring.

'3. In combination with a piston having a groove, a spring, expander ring seated in said groove and spaced from the inner wall groove, metallic triangular, circular,

4. In combinatlon w1th a piston having a split packing rings of such thinnessas to be capable of readily yielding on short segments of their circumferences, said rings being mounted in said groove, an inner expander member consisting of a split spring ring thickened ecceiitrically from'its'ends to a point opposite said ends, said expander ring extending across the width of the groove and having inclined outer faces fitting the inner faces of the outer rings and having side Walls extending inward parallel i to the sides of the groove from the base line of the inclined walls of the outer rings and having an inner wall joining the side walls and parallel with the inner wall of the groove.

5. In combination with a piston having a groove, an expander ring mounted in said groove and having exterior inclined faces, metallic packing rings of smaller cross section than the expander ring and of such thinness as to be yieldable on a short radius at any part of their circumferences so as to be capable of conforming at alLpoints to irregularities in the cylinder wall when pushed outwardly by the expander spring, said expander being eccentrically formed and the packing rings circular, and said expander ring being spaced from the inner wall of the piston groove, substantially as described.

In witness whereof, I have hereunto set my hand and seal at Indianapolis, Indiana, this 16th day of November, A. D. nineteen hundred and fourteen.

HARRY W. RANSDALL. [as] Witnesses: f

A. C. RICE, H. P. DOOLITTLE. 

